What is the approach for evaluating a chief complaint of headache in the emergency department?

Emergency Department Evaluation of Headache

The ED evaluation of headache must prioritize rapid identification of life-threatening secondary causes through focused history, neurological examination, and selective neuroimaging, followed by appropriate acute treatment once dangerous etiologies are excluded. 1

Initial Assessment: Red Flags for Secondary Headache

The first critical step is identifying features that suggest dangerous secondary causes requiring immediate investigation 1:

High-Risk Historical Features

• "Worst headache of my life" - present in 80% of subarachnoid hemorrhage (SAH) cases, though SAH accounts for only 1% of all ED headaches 1
• Sudden onset ("thunderclap") - particularly during physical exertion or sexual activity 1
• Sentinel/warning headache - occurs in 20% of patients 2-8 weeks before major SAH rupture 1
• New headache in older patients (>50 years) - higher risk of secondary causes 1
• Progressive worsening pattern over days to weeks 1
• Headache awakening patient from sleep 1
• Headache worsened by Valsalva maneuver 1

Critical Physical Examination Findings

• Focal neurological deficits - including cranial nerve palsies 1
• Altered mental status or loss of consciousness - reported in 53% of SAH patients 1
• Nuchal rigidity/meningismus - present in 35% of SAH cases 1
• Seizure activity - occurs in up to 20% of SAH patients, especially within first 24 hours 1
• Fever - suggests infectious etiology 2, 3

Diagnostic Workup Algorithm

Neuroimaging Decision-Making

Non-contrast head CT is the cornerstone diagnostic test and must be obtained when red flags are present 1:

• CT sensitivity for SAH: 98-100% within first 12 hours, declining to 93% at 24 hours and 57-85% at 6 days 1
• The most common diagnostic error is failure to obtain CT scan, associated with 4-fold higher mortality/disability 1

If CT is negative but clinical suspicion remains high, lumbar puncture is mandatory to detect xanthochromia and rule out SAH 1

Neuroimaging in Primary Headache

For patients without red flags presenting with typical migraine features 1:

• Normal neurological examination: neuroimaging usually not warranted 1
• Atypical features or not meeting strict migraine criteria: lower threshold for imaging 1
• Unexplained neurological findings: neuroimaging should be considered 1

Primary Headache Evaluation

Once secondary causes are excluded, focus on characterizing the primary headache disorder 1:

Essential Historical Elements

• Location: unilateral vs bilateral, frontal vs occipital, periorbital 1
• Duration: hours vs days 1
• Character: throbbing vs pressing/tightening 1
• Intensity: mild-moderate vs moderate-severe 1
• Associated symptoms: nausea/vomiting (77% of migraine), photophobia, phonophobia 1
• Aggravating factors: routine physical activity worsens migraine but not tension-type headache 1
• Aura symptoms: visual distortions, scotomas occurring before headache onset 1
• Trigger factors: hormonal changes, specific foods, missed meals, sensory stimuli 1
• Medication history: over-the-counter use, prescription medications, effectiveness, frequency of use 1
• Family history: migraine has genetic component 1

Medication Overuse Assessment

Critical to identify medication overuse headache, which occurs with frequent use of acute treatments 1:

• Frequency threshold: acute medication use more than 2 times per week increases risk 1
• High-risk medications: ergotamine, opiates, triptans, butalbital-containing compounds 1
• Pattern: increasing headache frequency progressing to daily headaches 1

Acute Treatment in the ED

For Migraine (Most Common Primary Headache in ED)

First-line parenteral therapy 2, 4:

• Anti-dopaminergic agents (metoclopramide, prochlorperazine) with diphenhydramine to prevent akathisia 2, 4
• NSAIDs (ketorolac 30-60mg IV) - rapid onset, 6-hour duration, low rebound risk 1, 2

Second-line options 2, 4:

• Divalproex sodium IV for status migrainosus 4
• Dihydroergotamine IV (contraindicated in coronary disease, uncontrolled hypertension, pregnancy) 4
• Corticosteroids (dexamethasone) to prevent recurrence 2, 4

Avoid opioids - poor effectiveness for migraine, risk of medication overuse headache and dependency 1, 2, 4

IV Fluids

Only indicated for documented dehydration - routine hydration not supported by evidence 2

Disposition and Follow-Up

Admission Criteria

Common reasons for admission include 5:

• Diagnostic uncertainty requiring prolonged observation (49% of admissions) 5
• Inadequate pain control in ED (33% of admissions) 5
• Serious secondary diagnosis requiring inpatient management (8% reveal potentially serious pathology) 5

Discharge Planning

Mandatory referral to headache specialist or neurology - lack of referral results in high ED recidivism rates 2, 4

Discharge instructions must include 1:

• Rescue medication plan for home use when treatments fail 1
• Education on medication overuse prevention 1
• Return precautions for red flag symptoms 6
• Scheduled follow-up within 2-3 months 1

Common Pitfalls to Avoid

• Failing to obtain CT when red flags present - most common error with highest morbidity 1, 6
• Misdiagnosing SAH as migraine - occurs in 12% of SAH cases, associated with 4-fold increased mortality 1
• Missing sentinel hemorrhage - 20% of major SAH preceded by warning leak 1
• Overusing opioids - ineffective for migraine, promotes dependency and rebound 1, 2
• Discharging without specialist referral - leads to repeated ED visits 2, 4
• Inadequate medication overuse screening - perpetuates chronic daily headache 1